One common theme is identity. Since she's Female Harry and the daughter of Hades, she often struggles to figure out who she really is in relation to both her wizarding self and her underworld heritage. Another theme is power. Her connection to Hades gives her unique powers, and stories often explore how she uses or struggles with these powers. For example, in some fanfictions, she has to learn to control her dark magic.
One great 'Female Harry, Daughter of Hades' fanfiction is 'The Underworld's Heir'. In this story, the female Harry has to navigate the complex world of being Hades' daughter while also dealing with the wizarding world. It has really interesting character development and unique plot twists. Another one is 'Shadows of the Underrealm'. Here, the author delves deep into the relationship between the female Harry and the other characters from the original series, with a dark and mysterious undertone that is really engaging.
One interesting fanfiction could be 'The Dark Daughter of Hades'. In this, the female Harry has to navigate the underworld politics while also dealing with the wizarding world's expectations. It shows her using her unique heritage to her advantage in battles and magical duels.
I recommend the novel, White Joy, to you. This was a modern romance novel about urban life. It told the story of the female protagonist, Bai Huanxin, who was adopted from birth. Although it was not explicitly mentioned that the female protagonist was adopted by Hades, this novel may meet your needs. I hope you like this recommendation!
One common theme is identity struggle. Since she's the daughter of Hades, she has to figure out where she belongs in both the wizarding world and the realm of the gods. Another theme is power and its control. Her powers from Hades are often very different from typical wizarding magic.
You can start by giving her a distinct personality. Maybe she's shy because she's always been feared for her father's sake. Then, gradually show her growing confidence as she discovers her own strengths. For example, if she has the power to raise small skeletons as minions, at first she's scared of it, but later she learns to use it for good. Also, explore her relationships with other characters. Her friendship with Percy could be based on mutual understanding of being different among the demigods.
The plot might involve Harry being drawn to the Forbidden Forest because of her Hades heritage. There could be a portal or some sort of underworld connection there. She could encounter dark creatures that are more in tune with her underworld side. And she might have to use her new - found powers to save Hogwarts from a threat that has roots in the underworld. For example, a powerful dark wizard is trying to raise an army of the dead and only Harry, with her connection to Hades, can stop it.
Hermione could be a popular character. In some fanfictions, she might accompany Harry to the Underworld and use her vast knowledge to help them solve problems. For example, she could be the one to decipher ancient Underworld texts that hold the key to their mission.
I really liked 'Fem Percy: Hades' Legacy'. It delved into her powers as the daughter of Hades. Since she's female, she might use her powers in a different way than the original Percy. She could be more in tune with the underworld's female spirits and use that connection to her advantage in battles and quests.
It could be a story of her self - discovery. She might initially be afraid of her powers as the daughter of Hades. But as she grows, she starts to learn more about her father's realm and how she can use her unique abilities for good. For example, she could use her connection to the underworld to help protect Hogwarts from some ancient dark magic that has a link to death and the afterlife.